Safety means for elevators.



M. T. WESTON. SAFETY MEANS FOR ELEVATORS.

APPLICATION FILED NOV. 23, 1905.

INVENTO/w Tan, 0, :4 1n: MORRIS PETERS ca., WASHING PATENTBD APR. so,1907.

4 SHEETS-411E121 1.

PATENTED APR. 30, 1907.

- M. T. WESTON.

SAFETY MEANS FOE ELEVATORS.

APPLIOATION TILED NOV. 23, 1905.

INVENTOR /T'MR WITNESSES THE. NORRIS PETE/es cm, wAsnmcmu n. c.

PATENTED APR. 30, 1907. MT. WESTON.

.SAPETY MEANS FOR ELEVATORS.

APPLICATION FILED NOV. 2a, 1905.

' 4 SHEETS-SHEET 3.

Fig.5.

INVENTOI? No.s52 ,04s. PATENTED APR. so, 1907.

\ M. T. WESTON.

SAFETY MEANS FOR ELEVATORS.

APPLICATION FILED NOV. 23, 1905.

4 SHEBTS-SHBET 4.

W/ TNE SSE S L0 lNVENTOR .TNE NORRIS FEIERS c0., WASHINGTON. n. c,

UNITE STATES PATENT OFFTOE.

MILTON T. WESTON, OF NEW YORK, N. Y., ASSIGNOR OF ONE-THIRD TO OATHARINEMAHONY AND ONE-THIRD TO ADOLPH A. SCI-LAEFER, OF

YONKERS, NEW YORK.

SAFETY MEANS FOR ELEVATORS.

Specification of Letters Patent.

Patented April 30, 1907.

Application filed November 23, 1905. Serial No. 288,692.

T0 or whom, it may concern:

Be it known that I, MILTON T. WEs'roN, a citizen of the United States,residing in the borough of Manhattan, city of New York, countyof NewYork, in the State of New York, have invented a certain new and usefulImprovement in Safety Means for Elevators, of which the following is aspecification.

This invention has relation to an improved means for attachment toelevators or hoists whereby the same are prevented from falling in casethe lifting cables break, or through other accident. WVhere the safetycatches or clutches, which are used for this purpose, operate with adegree of force independent of the weight of the car, they frequentlyfail to operate when a car is over-loaded when it begins to fall.

It is one object of this invention to provide means whereby the holdingforce exerted in supporting the car is made to a great extentproportional to the weight of the car itself.

Another olject of this invention, is to provide means of the characterabove named, which combine devices, for preliminary advance of theholding jaws, which devices also act to bring into play the mainmechanism for final closing of the aws or clutches.

My safety mechanism can be easily applied either beneath or on top ofthe car and occupies little room.

I have illustrated this invention in its preferred forms in theaccompanying drawings, wherein Figure 1 is a side elevation, with someparts shown in vertical section, of one form of my device attachedbeneath the car, Fig. 2 is a sectional detailed view on the plane a-b inFig. 1, Fig. 3 is a view similar to Fig. 1, of a modified form of myinvention and corresponding approximately to a section 011 the planec-(i, in Fig. 4, Fig. 1 is a vertical sectional View of the device shownin Fig. 3 taken on the two planes e-f and g. /t in Fig. 3, Fig. 5 is asectional detail on the plane m-n in Fig. 3, Fig. 6 is a similar viewshow ing the open position of the jaws and Fig. 7 is a sectional view ofthe device shown in Fig. 4: taken on the planes pg and aJ*-J.

In Fig. 1 the floor of the elevator is shown at 1 and the usual guidesfor the elevator are shown at 2. Beneath the floor the beams 3 supportin any appropriate manner the various parts of the safety device. Thiscomprises a casing 4, wherein is mounted a central shaft 5, on whichthere is fixed a carrier 6, supporting one or more pawls 7 which arepivoted to the carrier by means of pins 8, as shown in Fig. 2. Springs9, bear upon these pawls and tend to pull them outward, but thismovement is normally prevented by a pin 10, 011 each pawl, which bearsupon a guard plate 11, iixed to the stationary casing 1. The constantlyrotating worm wheel 12, is mounted so as to turn loosely on the shaft 5,and this worm wheel carries an interior ratchet whose teeth revolveoutside of and nearly in connection with the outer ends of the pawls 7.This ratchet is shown at 13. The worm wheel is driven by a worm 14,which turns whenever the car moves, being driven in any manner wellknown for devices of this kind. On the other end of the worm shaft asquared portion 16, is supplied,wherc by means may be applied forreverse move ment of the worm shaft when the device is to be reset afteroperation.

The gripping jaws which are intended to hold the elevator when thesafety device is applied, are shown at 17, in Figs. 1, 5 and 6. Theseare all well known constructions, being mounted on strong pivots 18, andsupplied with pivoted cams 19, to which are pivoted links 20, on theends of the tension rod 21.. The springs 22, bear upon adjustable disks23, fixed to the rods 21, and these springs therefore tend constantly todraw the rods toward the shaft 5, and to close the jaws on each side,down upon the guides 2. Each of the tension rods 21, is provided with aparallel o'll'set connecting rod 24 and the inner ends of theseconnecting rods are pivoted to the lever 25, which is made fast to theshaft 5, so that the two turn together. This is clearly shown in Fig. 7,and is shown in dotted lines in Fig. 1.

U nder normal conditions the lever 25 is held in the position in Fig. 1,wherein the pin 26, at the extremity of said lever is engaged by thehook 27 which is intended to be pulled downward at the proper time,through the agency of the lever 28 and connecting bar 29 operated by anyappropriate form of governor. One specific form of governor which Iprefer to use in this connection is shown in Fig. 7. This consists of ahollow pulley 30,

around which passes the usual safety rope 31, so that the pulleyrevolves constantly when the car is in motion. The pulley 30, turnsloosely upon the shaft 32 and at one end of said shaft, there is an arm33, shown in dotted lines in Fig. 7 and in full lines in Fig. 3. Theconnecting bar 29 is pivoted at one end to the outer end of the arm 33.Inside of the pulley 30 there is a jamming plate 34, which is mountedrigidly on the shaft 32 and is shaped substantially as shown in Fig. 7.A number of balls are carried within pulley 30 and, when the pulley 30turns rapidly enough, the forward ball of this group is jammed betweenthe interior of the pulley 30 and the edge of the plate 34. This causessolid engagement between the pulley and the plate and further revolutionof the pulley acts through the plate 34 to rotate the shaft 32 and thento operate through the bar 29 and lever 28 to pull down the hook 27 andrelease the main lever 26. Of course when the elevator is moving at anormal speed the balls 35 remain out of engagement with the edge of theplate 34,

and the pulley 30 runs idly.

Then the governor operates as above described, the lever 25, (see Fig.1), and the springs 22 act at once in the accomplishment of twofunctions. One effect of the springs is to close the jaws 17, withpreliminary pressure on the guides 2. This is merely to take up thesmall space which is normally left between the jaws and the guides, soas not to impede movement of the car. The second function accomplishedis rotation of the shaft 5, by means of the connections 24 and the lever25, and with the shaft 5, the plate 6 carried thereby. This rotationwill be produced in the direction of the arrow in Fig. 1, and, as thepawls 7 are carried with the plate 6, the pins 10 ride down the inclinedsurface on the fixed plate 11, thus permitting springs 9 to force thepawls outward into engagement with the teeth of the interior ratchetwheel, 13. As, has been already described, this ratchet wheel iscontinually revolving in the direction of the arrow in Fig. 1 owing tothe action of the worm 14 and the worm wheel 12. The consequence is,that the preliminary movement accomplished by the springs 22, *hen thele ver 25 is released from the hook 27, will be at once followed by afinal revolution of the shaft 5, due to engagement of the pawls 7, withthe ratchet wheel 13. This will cause a strong pressure to betransmitted through the tension rods 21, in closing the jaws 17, and thecar will thus be brought to rest by a force continually increasing aslong as motion of the car continues, which force will be roughlyproportional to the weight of the car andits load.

In Figs. 3, 4 and 7 I have shown another modification of my inventionbut embodying the same principles of action. In this form of the devicethe lever 25 is operated when released by means of a single curvedspring 36 instead of by spiral springs 22, and the shaft 5, instead ofcarrying pawls 7 for operation of the safety clutch, is furnished with aclutching disk 38, which is keyed to the shaft 5, as shown in Fig. 4.The worm wheel 12, surrounds the clutching disk 38, and the latter iscut out at intervals on its periphery, to receive rollers 39, which areprovided with pivots 40 extending in both directions through slightlyelongated holes 4] in the inner and outer operating plates 42 and 43.The plate 42 is carried by a hub 44, which turns loosely on the shaft 5,and is provided with clutch teeth 45, engaging with similar teeth 011the holding clutch 46 which surrounds the shaft 5, and slideslongitudinally upon a feather 47, whereby it is keyed to the shaft 5.The holding clutch 46 is provided with spiral peripheral slots 48, oneof which is shown in dotted lines in Fig. 4. The pins 49 are fixed tothe casing 4, and enter the slots 48. Inside cf the casing 4, the spiralspring 50, is attached to the casing and to the fastening 51, on theplate 42, in such manner as to tend to produce rotation of the plate 42,in a direction toward one looking at the drawing on the upper side ofthe shaft 5 in F ig. 4. As long as the parts arein the position shown inFigs. 3 and 4, the action of the spring 50 is resisted by the teeth 45,since the holding clutch 46 is prevented from turning by the shaft 5,which is held rigid by means of the lever 25 and hook 27. The inner andouter plates 42 and 43 are united by a stud 52, moving in a propercurved slot shown in dotted lines at 53 in Fig. 3. Both of the plates 42and 43 carry springs 54, which bear against the pivots 40, of therollers 39. As shown in Fig. 3, the direction of elongation of theholes, 41, through. which the pivots 40 pass, is such that the tendencyof the springs 54 is to prevent accidental outward move ment of therollers 39, which would produce premature contact with the surface ofthe constantly revolving worm wheel 12. The spaces for the rollers 39,are narrower at their forward ends than at the rear ends, where they areshown in Fig. 3. The operation of this form of the device is as follows:When the governor 30 moves with dangerous speed, owing to engagement ofthe usual safety rope 31, the hook 27 is tripped and the lever 25 isreleased. The spring 36, then throws the lever 25into the position inFig. 7 and the shaft 5 turns with the lever 25. The holding clutch 46being revolved with the shaft 5 and the spiral slots 48 engaging thepins 49, there will be produced a longitudinal movement of the holdingclutch 46 toward the left in Fig. 4. This will interrupt the engagementbetween the teeth 45 on the hub 44, and thereupon the spring 50 will befree to produce rotation of the plates .42 and 43 in the direction ofthe arrow in Fig.

3. The rollers 39 will be pressed forward by the springs 54 when therotation of the plates 42 and 43 takes place, and as soon as these lwhich insures engagement of all the rollers at 1 once. The furtherforward movement which will thus be imparted by the worm wheel 12,

to the disk 38, is transmitted through the shaft 5, and the lever 25 andbar 24 to the jaws 17, thus arresting downward movement of the car asheretofore described.

Many changes may be made in various parts of this device withoutdeparting from the spirit of my invention and I am not to be understoodas limiting myself to the" details hereon shown and described.

WVhat I claim is 1. In combination with the other elements of a safetydevice for elevators, a main shaft, a constantly moving operating wheelmounted loosely thereon, a lever fast on the shaft, a catching deviceconnected for operation with said lever, a clutch fast on said shaft forproducing engagement with said wheel when the shaft is rotated, a springand catch for said lever and a governor for releasing said catch,substantially as described.

2. In a safety device for elevators, gripping jaws, a main shaft, alever fast thereon, connected to said jaws, an operating wheel turningloosely on said shaft, a clutch fast on said shaft and operated bymovement thereof to connect the same to said wheel, a spring foroperating said lever, a eatch for said lever and a governor controllingsaid catch, substantially as described.

In a safety device for elevators, gripping jaws, a main shaft, anoperating wheel turning loosely thereon, a pivoted pawl carried by saidshaft so as to turn therewith, a ratchet on said. operating wheel, and aguard plate for holding said pawl out of engagement with said ratchetsubstantially as described.

L. A safety device for elevators, comprising gripping jaws, a main shaftfor operating the same, a constantly moving ratchet wheel, aspring-pressed pawl carried by said shaft and a guard plate for saidpawls having its operating surface so inclined as to hold said pawl awayfrom said ratchet in one position of said shaft, and to permitengagementbetween the pawl and ratchet in another position of saidshaft, substantially as described.

5. In safety device for elevators the combination of clutching means onthe moving cage and co-operating device extending along the shaft of theelevator with a governor shaft, a hollow pulley turning loosely thereon,a cable fixed at one end and extending along the shaft and around saidpulley, means connecting said shaft with said clutching means foroperation of the latter, a amming plate within said pulley and fastenedon said shaft and a loose ball within-said pulley and under said amniingplate, substantially as described.

' 6. A safety device for elevators comprising a casing, a pair ofgripping jaws, a tension rod connected with said jaws and passing intosaid casing, a worm wheel and worm within said casing, an exteriorpulley moved by motion of the elevator car, for turning said worm, andengaging means within said casing for bringing said tension rod intooperative relation to said worm wheel, substan tially as described.

MILTON T. WESTON.

W'itnesses HAROLD S. MACKAYE, KATHRYN B. CIIEEVERS.

